Connector assembly

ABSTRACT

A working member, particularly nuclear fuel, is held in place by a latched assembly. The latches are operated by a slidable sleeve working against a heavy spring. A pneumatic cylinder and piston pushes the slide against the spring, releasing the latches. The arrangement also compensates for creep or thermal expansion and, in one embodiment, relieves pressure surges.

United States Patent [151 3,635,793 Kolb et al. Jan. 18, 1972 [54] CONNECTOR ASSEMBLY 3,020,888 2/1962 Braun ..l76/36 ux 3,028,179 4/1962 Abramoska ..285/320 X [72] Inventors. Jack W. lg/o": Bob G. Smith, both of 3,364,120 1/1968 winders at alm 76/36 as 3,377,252 4/1968 Knights ....l76/36 [73] Assignee: The United States of America as 3,403,101 1 Sa ary 294/95 X represented b h U i d States Atomic 3,440,139 4/ 1969 Laplerre ....294/97 X Energy Commission 3,506,287 4/1970 Lampert 87/58 CT [22] Filed: 1969 Primary Examiner-Benjamin R. Padgett A L N 430 Assistant Examiner-E. E. Lehmann [21] pp 0 Attorney-Roland A. Anderson [52] U.S. Cl ..l76/87, 176/79, 285/316, 57] ABSTRACT 285/320, 176/76 511 lm. Cl ..oz1 21/00 A wmkmg member Pamculmly nuclear fuel held Place [58] Field 0 Search 176/76 77 287/1 19 58 by a latched assembly. The latches are operated by a slidable 316 97 sleeve working against a heavy spring. A pneumatic cylinder and piston pushes the slide against the spring, releasing the 56] References Cited latches. The arrangement also compensates for creep or thermal expansion and, in one embodiment, relieves pressure UNITED STATES PATENTS Surges- 3,020,88 7 2/1962 Hobson et al 176/36 X 8 Claims, 10 Drawing Figures iii a PATENTEU JAN 1 8 E472 sum 1 [IF 3 [72 2/612 tors k la Kalb CONNECTOR ASSEMBLY CONTRACTUAL ORIGIN Of THE INVENTION This invention was made in the course of or under a contract with the United States Atomic Energy Commission.

INTRODUCTION In nuclear reactors the fuel elements are mounted in tubes, from which they must be withdrawn at intervals .for replacement. Because of the intense radioactivity present, this must be done by remote handling. The holdown assembly for the fuel elements should, therefore, be readily removable. Because of the severe operating conditions, the assembly should, moreover, be able to compensate for metal creep and for thermal expansion and contraction while maintaining the integrity of the seals which are necessary to confine the cooling fluid.

GENERAL DESCRIPTION OF INVENTION We have devised a holddown assembly which meets the above requirements. While particularly designed for use in a liquid sodium-cooled fast flux test reactor, it will also have ap- THE DRAWINGS FIG. 1 is a view, partly in elevation and partly in section, of a first embodiment of the holddown assembly and its associated operating mechanism. The assembly is shown latched in place in the tube.

FIG. 2 is a view similar to FIG. 1, but with the assembly unlatched for removal from the tube. It also shows parts cutaway in a different manner, to supplement FIG. 1.

FIG. 3 isanexploded view of the elements shown in FIGS. 1 and 2.

FIG. 4 is a section taken on plane 4-4 of FIG. 2.

FIGJS is a section taken on the stepped planes 5-5 of FIG. 2.

FIG. 6 is asection taken on the stepped planes 6-6 of FIG. 2.

FIG. 7 shows an'alternate construction of aportion of the embodiment of FIGS. l-6.

FIG. 8 is -a view, :partially in section, of a second embodiment of the holddown assembly in the latched position.

FIG. 9 is a section taken on the stepped planes 99 of FIG. 8.

FIG. 10 is a fragmentary view of a portion of the embodiment of FIG. '8, showing the unlatched position.

DETAILED DESCRIPTION In the drawings, two embodiments of our invention are shown applied to a nuclear reactor, where they serve toretain a fuel subassemblyand associated instrumentation in place.

FIRST EMBODIMENT Referring to FIG. 1,-the fuel tube 3 contains fuel subassembly 5. The details of this subassembly are not material to A connector body 13 is threaded in pressure ring 7 and welded thereto at 15. The body 13 contains a bore 17 (see FIG. 6) within which are electrical conductors (not shown) terminating in a connector plug, which provides connection to the fuel assembly 5. The conductors extend out of bore 17 through a leadout tube 19.

A sleeve 23 surrounds connector body 13. It is freely slidable in tube 3 and also on connector body 13. Between sleeve 23 and pressure ring 7 is a spring 25, preferably a Belleville spring formed of pairs of frustoconical spring washers having opposed apices. This type spring is suitable for the transmission of very high loads.

Sleeve 23 is provided with radial slots 230 through which extend latches 29, each having a head 29a and a shank 2%. A guide pin 31 through shank 29b pivotally mounts latch 29 in guide fins 32, 32 passing through guide bores 33. Fins 32 are integral with, or welded to, body 13. Bores 33 are vertically elongated or are made oversize relative to pin 31, so as to permit play of at least several hundredths of an inch. Pins 31 are not intended to take heavy loads, this being done by heads 29a, as will be explained later.

The lower end of each head 29a has a lower pressure surface 290, while sleeve 23 is formed with cooperating pressure faces 23b. The inner surface of each latch 29 is formedwith a cam surface 29d while sleeve23 is provided with cam follower surfaces 23c. The upper end 29c of shank 29b extends outwardly from pin 31 forming an upper abutment surface which engages the upper end of slot 23a on downward movement of sleeve 23.

Finally, each head 29a is provided with an upwardly facing abutment 29f which engages a downwardly facing abutment 35 formed on the inner surface of tube 3. The latter abutment is formed by a channel 37 machined in the wall of tube 3.

Body 13 is formed at its upper end with adapter splines 39, whose function will be described later.

NORMAL POSITION, FIGURE 1 When the assembly is in normal operating condition, as shown in FIG. 1, the spring 25 is about 50 percent compressed. The cam follower 230 has tipped each latch 29 outwardly so that its upwardly facing .abutrnent 29f engages a downwardly facing-abutment '35.

Each pin 31 is riding loosely in a bore 33. Spring 25 is compressed between sleeve 23 and pressure ring 7, forcing the latter down against subassembly :5 and seals 9 and 1 1 while the sleeve is held against latches .29. The lower portion of the structure shown fuel subassembly '5, pressure ring 7, and the corresponding parts of tube 3 operate at alternate high and low temperatures. Due to the loose fit of pins 31 in bores 33 and the constant-pressure of spring 25 against pressure ring 7, expansionand contraction, or permanent creep can take place while constantpressure is maintained on the seal.

*DISCONNECTION Refer now to FIGS. 11, I2, -4 .andS. We utilize a hydraulic cylinder 41 having a piston i43. Mounted on the cylinder is a bifurcated adapter 45 formedto mate-with splines 39 of body 13. On the ;piston. is a U-shaped pressure member 47 having flat ends shaped to fitagainst sleeve .23.

With the piston 43 retracted, adapter-45 is slippedover adapter splines 39:and thengiven a 45 tumJ-Iydraulic pressure is then applied to the piston. This causes the U-shaped pressure member to force sleeve 23 downwardly, against springl'S, to the position shown in;-FIG. 2, disengaging the pressure surfaces23b of sleeve 23 from'29c of latches 129. The upper ends of slots f23aengagetheupper abutmentsurfaces 29e of latches 29,tippingthe latches so that their upwardly facing abutment'29f are disengaged-from downwardly facing 'abutments 35.'The entire assemblage can then be withdrawn from the tube'3. Reinsertion is madein an obvious'reversal of thesesteps.

'It should be understood.that'the'hydraulic cylindervAl is present only during the insertion and removal operations.

As stated above, the sealing arrangement may take a number of different forms. As an illustration, we have shown an alternate construction in FIG. 7.

In this modification, the tube 53, corresponding to tube 3 in the foregoing figures is welded to adapter 54, which is provided with an internal shoulder 55. The shoulder is engaged by connector flange 57 of the fuel subassembly 59. Between them is a metallic K seal 61. Pressure ring 63 engages flange 57 and forces against seal 61. Otherwise, the structure and operation is the same as already described.

SECOND EMBODIMENT FIGS. 8, 9 and 10 show a modified construction in which the latches are mounted on the sleeve rather than on the body. This is our presently preferred embodiment.

In these figures the pressure ring is shown at 107, its seal is with tube 3 and the fuel element (not shown) at 111. Secured to the ring is a body 113. The sleeve is shown at 123 and the Belleville spring at 125. These parts have the same relationship as the modification of FIGS. 1-7.

Each latch 129 is provided with an operating nose 161. A frustoconical spring washer 163 is held in place on connector body 113 by retaining ring 165 and the connector body is formed with an annular cam surface 167. Washer 163 and cam surface 167 engage noses 161 to operate latches 129.

The disconnection of this embodiment utilizes the same hydraulic cylinder 41 and piston 43 shown in FIGS. 1-4. Starting with the parts in the position shown in FIG. 8, the sleeve 123 is pushed downwardly to the position shown in FIG. 10. During this relative movement, noses 161 engage the washers 163, tilting the latches away from tube 3, as shown, and permitting withdrawal of the assembly.

On reinsertion, when the pressure is released on sleeve 123, spring 125 causes it to return to the position shown in FIG. 8. During this movement, noses 161 engage cam surface 167, tilting latches 129 into engagement with shoulders 135.

An advantage of this embodiment over that of FIGS. 1-7 resides in its ability to yield in response to pressure surges and permit release of pressure in tube 3. When such a surge takes place, pressure ring 107 rises, compressing spring 125 and deflecting washer 163. This temporarily breaks seal 111, allowing fluid to escape around pressure ring 107 and ring 123. On release of the pressure, spring 125 returns the ring 107 to its original position. This is accomplished without releasing or damaging latches 129. (In the modification of FIGS. 1-7 such movement, without damage, is limited to the clearance provided by oversize bores 33.)

We claim:

1. A creep-compensatory connector assembly comprising a tube; a working member in said tube; a pressure ring slidably fitting in said tube, engaging said working member and supporting it in a position fixed with respect to said tube; an elongated axial connector body rigidly secured to said pressure ring; a sleeve slidably fitting in said tube and surrounding said connector body; a compression spring between and engaging said pressure ring and said sleeve and urging them apart; said tube, ring, connector body and sleeve being coaxial; said connector body and said sleeve forming a pair of latch-operating members; at least one latch having a shank and a head, pivotally mounted on one of said latch-operating members on an axis through and normal to said shank, said axis being transverse to the axis of said members; said latch extending through a slot in said sleeve and having an outer surface adjacent said tube, the head of said latch extending outward from said shank toward said tube, said head having an upwardly facing abutment; said tube having on its inner surface a downwardly facing abutment positioned to engage said upwardly facing abutment of said head of said latch; said latch having a downwardly facing pressure surface on the bottom side of its head; said sleeve having an upwardly facing pressure surface opposing and engaging said downwardly facing pressure surface of said head of said latch; said pressure surfaces engaging under the pressure of said spring against said sleeve,

said abutment surfaces likewise engaging under the pressure of said spring; latch-engaging means mounted on the other of said latch-operating members engaging said latch in such a manner that when said sleeve is forced upwardly by said spring, said latch is tilted outwardly into engagement with said downwardly facing abutment, while when said sleeve is pushed downwardly against the force of said spring, said latch is tilted inwardly out of engagement with said downwardly facing abutment, whereby said connector body, sleeve, spring and ring may be withdrawn upwardly from said tube.

2. An assembly as defined in claim 1 wherein said connector body comprises circumferentially spaced splines positioned beyond the end of said tube and, associated with said device, an operating mechanism comprising a pneumatic cylinder and piston, and means connected to said cylinder and piston for pulling on said splines while pushing on said sleeve to thereby force said ring downwardly against the force of said spring.

3. An assembly as defined in claim 1 wherein said tube is a nuclear reactor fuel tube and said working member is a nuclear fuel assembly.

4. An assembly as defined in claim 1, wherein said latch is pivoted on said connector body and wherein said latch has an upper edge forming an upper pressure surface extending through the slot in the sleeve positioned to be engaged by the upper edge of said slot when said sleeve is pushed downward against the force of said spring, thereby tilting said latch out of engagement with said downwardly facing abutment; and the inner edge of said latch defines a cam surface; said sleeve having cam follower surfaces opposing the cam surface of said latch such that when said sleeve is forced upwardly by the spring said sleeve cam follower surface engages said cam surface so as to tilt said latch into engagement with said downwardly facing abutment with the sleeve pressed against the lower pressure surface of the latch.

5. An assembly as defined in claim 1, wherein said latch is pivoted on said sleeve, and wherein said latch is mounted in the slot in said sleeve, said latch having at its upper end an inwardly extending nose, a first engagement member on said connector body above said nose, said first engagement member having a surface opposing said nose positioned so as to engage said nose when said sleeve is forced upwardly by said spring and tilt said latch into engagement with said downwardly facing abutment, and a second engagement member on said connector body below said nose, said second engagement member having a surface opposing said nose positioned so as to engage said nose when said sleeve is pushed downwardly against the force of said spring and tilt said latch out of engagement with said downwardly facing abutment.

6. An assembly as defined in claim 5, wherein said second engagement member is a stiff spring, thereby permitting limited upward movement of said connector body, when said latch is engaged.

7. An assembly as defined in claim 6, wherein there are a plurality of latches evenly spaced about the periphery of said sleeve, said first engagement member is an annular shoulder, and said second engagement member is an upwardly diverging frustoconical spring washer.

8. An assembly as defined in claim 4 wherein a pin extending through, a vertically elongated bore in a guide fin attached to the connector body pivotally mounts said latch on said connector body. 

1. A creep-compensatory connector assembly comprising a tube; a working member in said tube; a pressure ring slidably fitting in said tube, engaging said working member and supporting it in a position fixed with respect to said tube; an elongated axial connector body rigidly secured to said pressure ring; a sleeve slidably fitting in said tube and surrounding said connector body; a compression spring between and engaging said pressure ring and said sleeve and urging them apart; said tube, ring, connector body and sleeve being coaxial; said connector body and said sleeve forming a pair of latch-operating members; at least one latch having a shank and a hEad, pivotally mounted on one of said latch-operating members on an axis through and normal to said shank, said axis being transverse to the axis of said members; said latch extending through a slot in said sleeve and having an outer surface adjacent said tube, the head of said latch extending outward from said shank toward said tube, said head having an upwardly facing abutment; said tube having on its inner surface a downwardly facing abutment positioned to engage said upwardly facing abutment of said head of said latch; said latch having a downwardly facing pressure surface on the bottom side of its head; said sleeve having an upwardly facing pressure surface opposing and engaging said downwardly facing pressure surface of said head of said latch; said pressure surfaces engaging under the pressure of said spring against said sleeve, said abutment surfaces likewise engaging under the pressure of said spring; latch-engaging means mounted on the other of said latch-operating members engaging said latch in such a manner that when said sleeve is forced upwardly by said spring, said latch is tilted outwardly into engagement with said downwardly facing abutment, while when said sleeve is pushed downwardly against the force of said spring, said latch is tilted inwardly out of engagement with said downwardly facing abutment, whereby said connector body, sleeve, spring and ring may be withdrawn upwardly from said tube.
 2. An assembly as defined in claim 1 wherein said connector body comprises circumferentially spaced splines positioned beyond the end of said tube and, associated with said device, an operating mechanism comprising a pneumatic cylinder and piston, and means connected to said cylinder and piston for pulling on said splines while pushing on said sleeve to thereby force said ring downwardly against the force of said spring.
 3. An assembly as defined in claim 1 wherein said tube is a nuclear reactor fuel tube and said working member is a nuclear fuel assembly.
 4. An assembly as defined in claim 1, wherein said latch is pivoted on said connector body and wherein said latch has an upper edge forming an upper pressure surface extending through the slot in the sleeve positioned to be engaged by the upper edge of said slot when said sleeve is pushed downward against the force of said spring, thereby tilting said latch out of engagement with said downwardly facing abutment; and the inner edge of said latch defines a cam surface; said sleeve having cam follower surfaces opposing the cam surface of said latch such that when said sleeve is forced upwardly by the spring said sleeve cam follower surface engages said cam surface so as to tilt said latch into engagement with said downwardly facing abutment with the sleeve pressed against the lower pressure surface of the latch.
 5. An assembly as defined in claim 1, wherein said latch is pivoted on said sleeve, and wherein said latch is mounted in the slot in said sleeve, said latch having at its upper end an inwardly extending nose, a first engagement member on said connector body above said nose, said first engagement member having a surface opposing said nose positioned so as to engage said nose when said sleeve is forced upwardly by said spring and tilt said latch into engagement with said downwardly facing abutment, and a second engagement member on said connector body below said nose, said second engagement member having a surface opposing said nose positioned so as to engage said nose when said sleeve is pushed downwardly against the force of said spring and tilt said latch out of engagement with said downwardly facing abutment.
 6. An assembly as defined in claim 5, wherein said second engagement member is a stiff spring, thereby permitting limited upward movement of said connector body, when said latch is engaged.
 7. An assembly as defined in claim 6, wherein there are a plurality of latches evenly spaced about the periphery of said sleeve, said first engagement member is an annular shoulder, and said second engAgement member is an upwardly diverging frustoconical spring washer.
 8. An assembly as defined in claim 4 wherein a pin extending through a vertically elongated bore in a guide fin attached to the connector body pivotally mounts said latch on said connector body. 